Hygroryza

Scientific name

Hygroryza Nees

Common names

Asian root floater, watergrass

Family

Poaceae

Similar genera

Luziola, Sphaerocaryum

Native distribution

India, Sri Lanka, Pakistan, China

Species cultivated

Hygroryza aristata (Retz.) Nees

Adventive distribution

Thailand, Indonesia, Bangladesh

Weed status

significant weed species in rice in parts of Asia

Habit

floating, branching grass with inflatedinflated:
(adj) bladdery; swollen, or appearing so
leaf sheaths

Brief description

Perennialperennial:
(adj) (of a plant) having a life cycle of more than two years
grass. Stoloniferous, culms creeping or ascending, floating, with roots produced at internodes. Leaves floating or emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
entireentire:
(adj) having a continuous margin that is not toothed or lobed
, ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
to ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
-oblong, olive green, venationvenation:
(n) the arrangement of veins in a leaf
parallel with distinct pale midveinmidvein:
(n) the primary, usually central vein of a leaf or leaflet
; leaf sheath inflatedinflated:
(adj) bladdery; swollen, or appearing so
with aerenchymaaerenchyma:
(n) plant tissue with large, gas-filled intercellular spaces that facilitates gaseous exchange and maintains buoyancy
. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
a paniclepanicle:
(n) an indeterminate, branched (often much-branched) inflorescence; the ultimate units may be of a different inflorescence type
; spikelets single flowered. Floretfloret:
(n) one of the small individual flowers within a dense cluster of flowers, as in a compound inflorescence and in grass spikelets
with long awn. Dispersal by stem fragments and seeds.

Natural habitat

still waters of lakes, ponds, canals, and flooded rice fields

Additional comments

Hygroryza aristata, the sole species in the genus, is one of the few grasses that is regularly cultivated for aquaria or ponds. Hygroryza has inflatedinflated:
(adj) bladdery; swollen, or appearing so
leaf sheaths to aid in flotation and can form dense, floating mats.